1. Field of the Invention
The present invention relates to electro-photographic image forming apparatuses capable of mounting a belt unit that contacts a recording material and forming an image on the recording material.
2. Description of the Related Art
In electro-photographic image forming apparatuses (laser beam printers, copying machines, facsimile apparatuses, and the like), some image forming apparatus bodies include an opening and closing member to enable attachment of a unit to the inside of the body for replacement or maintenance of the unit.
Japanese Patent Application Laid-Open No. 2009-145623 discusses a structure for enabling attachment of a belt unit including an intermediate transfer belt to a body.
However, in such a structure in which the belt unit can be attached to the body, in a state where the belt unit is not attached to the body, if an image is formed onto a recording material, the following problem may occur. That is, when the belt unit is not attached to the body, at the position at which the recording material and the belt contact, since the recording material cannot be conveyed with the belt, the recording material is not properly conveyed, and this may cause a jam.